A 100-litre aquarium rain simulator: build brief and test plan

Planned volume

100 litres

Mist heads

9

Purpose

Controlled spawning-trigger experiment

Status

Build brief, not proven result

Start with the question, not the hardware

The AquaNexus project notes describe a 100-litre rain simulator with nine mist heads. The build is only useful if it answers a defined question: does a controlled change in surface disturbance, temperature or water chemistry coincide with spawning in a specific conditioned group?

Without that question, the simulator becomes an impressive-looking spray bar whose effect cannot be separated from feeding, weather, water changes or normal breeding readiness.

Distribute water evenly enough to test the idea

Nine heads should not create nine violent jets. The layout needs even coverage, stable pressure and a return path that does not flood the room or expose electrical equipment. Each head should be accessible for cleaning because small openings change flow as they foul.

1. Map the spray area.Mark dry zones, heavy impact points and overflow risk.
2. Measure total flow.Do not rely on pump rating after pipe losses and nine restrictions.
3. Check temperature.Measure source water, tank water and the change during the event.
4. Test without fish.Run the complete cycle and inspect leaks, noise and aeration.
5. Set an emergency stop.The operator must be able to stop flow immediately without reaching through wet wiring.

Rain simulation can change more than surface movement

Added water can alter temperature, hardness, conductivity, pH and dissolved gases. If the goal is to test surface disturbance, those other variables should remain as stable as practical. If the goal is to test a cooler water event, the temperature change should be measured rather than described as “cool”.

Record a baseline before the event

• Species, group ID, sex estimate and conditioning period.
• Previous spawning date or no-spawn period.
• Water temperature, pH and other relevant source-water measures.
• Feeding during the previous week.
• Weather and barometric observations if they are part of the hypothesis.
• Normal pump, air and lighting routine.

Define the event precisely

Record start time, duration, volume added or recirculated, head configuration and any change in flow. If the system recirculates the same water, say so. If it introduces new water, record the amount and preparation.

Observe more than spawning

Record activity, schooling, courtship, respiration, hiding and aggression during and after the event. A spawn is an outcome, but stress is also an outcome. Note when eggs appear and whether spawning continues after the simulator stops.

Use repeated controlled trials

One spawn after one rain event proves very little because the group may already have been ready. Repeat the same method, include no-trigger observation periods where practical and change one variable at a time.

What must be true before publishing a result

The page should identify species, group, exact method, number of trials, no-result trials and any adverse response. A successful spawn should not be turned into a universal recipe.

The prototype is valuable even if it does not increase spawning. A well-recorded negative result can prevent future keepers from repeating an uncontrolled build and calling coincidence evidence.